Variable resistance memory device and method of manufacturing the same

ABSTRACT

A variable resistance memory device and a method of manufacturing the same, the variable resistance memory device including a substrate including a first memory region and a second memory region; a plurality of first memory cells on the first memory region; and a plurality of second memory cells on the second memory region, wherein each of the first memory cells includes a first resistance element and a selection element, each of the second memory cells includes a second resistance element, and a maximum value of a variable resistance of the second resistance element is less than a maximum value of a variable resistance of the first resistance element.

CROSS-REFERENCE TO RELATED APPLICATION

Korean Patent Application No. 10-2019-0037384, filed on Mar. 29, 2019,in the Korean Intellectual Property Office, and entitled: “VariableResistance Memory Device and Method of Manufacturing the Same,” isincorporated by reference herein in its entirety.

BACKGROUND 1. Field

Embodiments relate to a variable resistance memory device and a methodof manufacturing the same.

2. Description of the Related Art

Semiconductor devices may be categorized as any one of memory devicesand logic devices. The memory devices may store logical data.Semiconductor memory devices may be classified into volatile memorydevices and non-volatile memory devices. The volatile memory devices maylose their stored data when their power supplies are interrupted. Forexample, the volatile memory devices may include dynamic random accessmemory (DRAM) devices and static random access memory (SRAM) devices. Onthe contrary, the non-volatile memory devices may retain their storeddata even when their power supplies are interrupted. For example, thenon-volatile memory devices may include programmable ROM (PROM),erasable PROM (EPROM), electrically EPROM (EEPROM), and a flash memorydevice.

SUMMARY

The embodiments may be realized by providing a variable resistancememory device including a substrate including a first memory region anda second memory region; a plurality of first memory cells on the firstmemory region; and a plurality of second memory cells on the secondmemory region, wherein each of the first memory cells includes a firstresistance element and a selection element, each of the second memorycells includes a second resistance element, and a maximum value of avariable resistance of the second resistance element is less than amaximum value of a variable resistance of the first resistance element.

The embodiments may be realized by providing a method of manufacturing avariable resistance memory device, the method including forming a bottomelectrode material layer on a substrate that includes a first memoryregion and a second memory region; forming a first variable resistancematerial layer on the bottom electrode material layer; forming a firsttop electrode material layer on the first variable resistance materiallayer; removing the first variable resistance material layer and thefirst top electrode material layer on the second memory region; forminga second variable resistance material layer on the substrate; forming asecond top electrode material layer on the second variable resistancematerial layer; removing the second variable resistance material layerand the second top electrode material layer on the first memory region;and patterning the bottom electrode material layer, the first variableresistance material layer, the second variable resistance material layerand the first and second top electrode material layers, which remain onthe substrate, to form first memory cells on the first memory region andsecond memory cells on the second memory region, wherein removing thesecond variable resistance material layer and the second top electrodematerial layer on the first memory region includes performing aplanarization process to expose the first top electrode material layeron the first memory region, and the first variable resistance materiallayer includes a material of which a maximum resistance value isdifferent from that of a material of the second variable resistancematerial layer.

BRIEF DESCRIPTION OF THE DRAWINGS

Features will be apparent to those of skill in the art by describing indetail exemplary embodiments with reference to the attached drawings inwhich:

FIG. 1 illustrates a schematic block diagram of a variable resistancememory device according to some embodiments.

FIG. 2 illustrates a cross-sectional view of a variable resistancememory device according to some embodiments.

FIGS. 3A to 3I illustrate cross-sectional views of stages in a method ofmanufacturing a variable resistance memory device according to someembodiments.

FIG. 4 illustrates a cross-sectional view of a variable resistancememory device according to some embodiments.

FIGS. 5A to 5F illustrate cross-sectional views of stages in a method ofmanufacturing a variable resistance memory device according to someembodiments.

FIG. 6 illustrates a cross-sectional view of a variable resistancememory device according to some embodiments.

FIGS. 7A to 7F illustrate cross-sectional views of stages in a method ofmanufacturing a variable resistance memory device according to someembodiments.

DETAILED DESCRIPTION

Variable resistance memory devices and methods of manufacturing the sameaccording to embodiments will be described hereinafter in detail withreference to the accompanying drawings.

FIG. 1 illustrates a schematic block diagram of a variable resistancememory device according to some embodiments.

Referring to FIG. 1, a variable resistance memory device 1000 accordingto some embodiments may include a first memory device MD1 and a secondmemory device MD2. The first memory device MD1 may include a metal oxideresistance element or an interfacial operation resistance element. Aread/write latency of the first memory device MD1 may range fromhundreds of ns (nanoseconds) to several μs (microseconds) or more. Thefirst memory device MD1 may have similar characteristics to those of aflash memory device.

The second memory device MD2 may include a magnetic resistance element,a phase change element, or a metal oxide resistance element. Aread/write latency of the second memory device MD2 may range fromseveral ns to several tens of ns or more. For example, the second memorydevice MD2 may have similar characteristics to those of a SRAM device ora DRAM device.

A retention characteristic of the first memory device MD1 may be greaterthan that of the second memory device MD2, and an operating speed of thefirst memory device MD1 may be less than that of the second memorydevice MD2. The second memory device MD2 may be used as a buffersupplementing relatively low speed and performance of the first memorydevice MD1, and thus efficiency of the variable resistance memory device1000 may be improved or increased.

The variable resistance memory device 1000 may further include an EPROMM1, a central processing unit (CPU) M2, an input/output (I/O) M3, aserial interface M4, and a timer M5. For example, the variableresistance memory device 1000 may be formed or realized as one ofvarious semiconductor devices including the first and second memorydevices MD1 and MD2. The variable resistance memory device 1000 may beformed as a single independent memory chip.

FIG. 2 illustrates a cross-sectional view of a variable resistancememory device according to some embodiments.

Referring to FIG. 2, a variable resistance memory device 2000 accordingto some embodiments may include a substrate 100, a first memory deviceMD1, and a second memory device MD2. The substrate 100 may include afirst memory region AR1 and a second memory region AR2.

An interlayer insulating layer 101 may be on the substrate 100, and aplurality of first conductive lines CL1 may be in the interlayerinsulating layer 101 on the first memory region AR1. The plurality offirst conductive lines CL1 may be, e.g., word lines or bit lines. Eachof the first conductive lines CLI may extend in a first direction D1parallel to a top surface of the substrate 100. In an implementation,top surfaces of the first conductive lines CL1 may be coplanar with atop surface of the interlayer insulating layer 101.

The first memory device MD1 may be on the first memory region AR1. Thefirst memory device MD1 may include a plurality of first memory cellsMC1. The first memory cells MC1 may be spaced apart from each other in asecond direction D2 which is parallel to the top surface of thesubstrate 100 and is perpendicular to the first direction D1.

Each of the first memory cells MC1 may include a first resistanceelement RD1 and a selection element SW. Each of the first memory cellsMC1 may further include a sub-bottom electrode BS. The sub-bottomelectrode BS, the selection element SW, and the first resistance elementRD1 may be sequentially stacked in a third direction D3 perpendicular tothe top surface of the substrate 100. The sub-bottom electrode BS mayinclude a single metal electrode layer or a plurality of metal electrodelayers.

The selection element SW may be an element based on a thresholdswitching phenomenon having a nonlinear I-V curve (e.g., a S-shaped I-Vcurve). In an implementation, the selection element SW may include,e.g., an ovonic threshold switch (OTS) element having a bi-directionalcharacteristic, a PN diode, or a mixed ionic electronic conductor(MIEC). The selection element SW may include a chalcogenide material.The chalcogenide material may include a compound which includes achalcogen element (e.g., Te and/or Se) and at least one of Ge, Sb, Bi,Al, Pb, Sn, Ag, As, S, Si, In. Ti, Ga, or P. In an implementation, theselection element SW may further include an impurity, e.g., C, N, B, orO. As used herein, the term “or” is not an exclusive term, e.g., “A orB” could include A, B, or A and B.

Each of the first memory cells MC1 may be at a crossing point of thefirst conductive line CL1 and a second conductive line CL2 to bedescribed below, thereby forming a cross point structure. In this case,the selection element SW may help inhibit a leakage current occurring inthe cross point structure.

The first resistance element RD1 may include a first bottom electrodeBE1, a first variable resistance pattern RP1, and a first top electrodeTE1, which are sequentially stacked in the third direction D3.

The first bottom electrode BE1 and the first top electrode TE1 mayindependently include, e.g., W, Pt, Ru, Ti, Hf, Zr, Ta, an oxidethereof, or a nitride thereof. Each of the first bottom electrode BE1and the first top electrode TE1 may include a single layer or aplurality of layers. The plurality of layers may include different kindsof layers including Ti and/or W. In an implementation, the differentkinds of layers may include, e.g., Ti/TiN, Ti/TiN/W, or WN/W.

The first bottom electrode BE1 and the first top electrode TE1 mayinclude the same material or may include different materials.

The first variable resistance pattern RP1 may be an element of which astate is changed from a high-resistance state into a low-resistancestate by a voltage or is changed from the low-resistance state into thehigh-resistance state by a voltage. The first variable resistancepattern RP1 may include an oxide (e.g., a metal oxide) including Ti, Zr,Al, Hf, or Si. The first variable resistance pattern RP1 may have asingle-layered structure. In an implementation, the first variableresistance pattern RPI may have a barrier shape or a multi-layeredstructure (e.g., a double-layered structure or more), depending on anintended use. For example, the first variable resistance pattern RP1 mayhave the barrier shape to adjust operating voltage and current or mayhave the multi-layered structure to improve switching ability.

The second conductive line CL2 may be on the first memory device MD1.The second conductive line CL2 may extend in the second direction D2.The second conductive line CL2 may be electrically connected to thefirst memory cells MC1. The second conductive line CL2 may be, e.g., aword line or a bit line. The first conductive line CL1 and the secondconductive line CL2 may intersect each other when viewed in a plan view.The first conductive line CL1, the first memory cell MC1 and the secondconductive line CL2 may constitute the cross point structure. In animplementation, as illustrated in FIG. 2, the structure (1S1R) may beone in which one first resistance element RD1 and one selection elementSW are electrically connected to each other.

In an implementation, a transistor TR, a source line SL, a word line WLand other semiconductor component may be provided in the second memoryregion AR2.

A plurality of conductive patterns CP may be provided in the interlayerinsulating layer 101 on the second memory region AR2. In animplementation, top surfaces of the conductive patterns CP (e.g.,surfaces facing away from the substrate 100) may be coplanar with thetop surface of the interlayer insulating layer 101. The plurality ofconductive patterns CP may transmit electrical signals between thetransistors TR and second memory cells MC2 to be described below. In animplementation, as illustrated in FIG. 2, each of the second memorycells MC2 may be connected to each of the transistors TR (1T1R). In animplementation, the number of the connected transistor TR may bedifferent from that illustrated.

The second memory device MD2 may include a plurality of the secondmemory cells MC2. The second memory cells MC2 may be spaced apart fromeach other in the second direction D2.

Each of the second memory cells MC2 may include a second resistanceelement RD2. Each of the second memory cells MC2 may further include asub-bottom electrode BS. The sub-bottom electrode BS and the secondresistance element RD2 may be sequentially stacked in the thirddirection D3.

The second resistance element RD2 may include a second bottom electrodeBE2, a second variable resistance pattern RP2, and a second topelectrode TE2, which are sequentially stacked in the third direction D3.

The second bottom electrode BE2 and the second top electrode TE2 mayindependently include, e.g., W, Pt, Ru, Ti, Hf, Zr, Ta, an oxidethereof, or a nitride thereof. Each of the second bottom electrode BE2and the second top electrode TE2 may include a single layer or aplurality of layers. The plurality of layers may include different kindsof layers including Ti and/or W. In an implementation, the differentkinds of layers may include Ti/TiN, Ti/TiN/W, or WN/W.

The second bottom electrode BE2 and the second top electrode TE2 mayinclude the same material or may include different materials.

The second variable resistance pattern RP2 may be an element of which astate is changed from a high-resistance state into a low-resistancestate by a voltage or is changed from the low-resistance state into thehigh-resistance state by a voltage. The second variable resistancepattern RP2 may include at least one of an oxide (e.g., a metal oxide)including, e.g., Ti, Zr, Al, Hf, or Si. The second variable resistancepattern RP2 may have a single-layered structure. In an implementation,the second variable resistance pattern RP2 may have a barrier shape or amulti-layered structure (e.g., a double-layered structure or more),depending on an intended use. For example, the second variableresistance pattern RP2 may have the barrier shape to adjust operatingvoltage and current or may have the multi-layered structure to improveswitching ability.

A third conductive line CL3 may be on the second memory device MD2. Thethird conductive line CL3 may be electrically connected to a pluralityof the second memory cells MC2. The third conductive line CL3 may be,e.g., a bit line. The second memory device MD2 may have an embeddedstructure.

In an implementation, as illustrated in FIG. 2, the structure (1T1R) maybe one in which one second resistance element RD2 and one transistor TRare electrically connected to each other.

In relation of the first memory device MD1 and the second memory deviceMD2, the second variable resistance pattern RP2 may include a differentmaterial from that of the first variable resistance pattern RP1. Whenthe same voltage is applied to the first and second variable resistancepatterns RP1 and RP2, the amount of a current flowing through the secondvariable resistance pattern RP2 may be more than the amount of a currentflowing through the first variable resistance pattern RP1. For example,the first variable resistance pattern RP1 may have a resistance statethat is greater than that of the second variable resistance pattern RP2.In an implementation, a maximum value of a variable resistance of thesecond resistance element RD2 may be less than a maximum value of avariable resistance of the first resistance element RD1.

A level (e.g., a height or distance from the substrate 100 in the thirddirection D3) of a top surface T1 of the first top electrode TE1 may bethe same or substantially the same as a level of a top surface T2 of thesecond top electrode TE2. A level of a top surface B1 of the firstbottom electrode BE1 may be the same or substantially the same as alevel of a top surface B2 of the second bottom electrode BE2.

A level of a top surface of the sub-bottom electrode BS on the firstmemory region AR1 may be the same as a level of a top surface of thesub-bottom electrode BS on the second memory region AR2. The selectionelement SW may be on the first memory region AR1, and a level of abottom (e.g., substrate-facing) surface of the first bottom electrodeBE1 may be higher than a level of a bottom surface of the second bottomelectrode BE2. In an implementation, a width (e.g., thickness, verticallength, or height) of the first resistance element RD1 in the thirddirection D3 may be less than a width (e.g., thickness, vertical length,or height) of the second resistance element RD2 in the third directionD3.

FIGS. 3A to 3I illustrate cross-sectional views of stages in a method ofmanufacturing a variable resistance memory device according to someembodiments.

Referring to FIG. 3A, a substrate 100 including a first memory regionAR1 and a second memory region AR2 may be provided. An interlayerinsulating layer 101 and first conductive lines CL1 therein may beprovided on the first memory region AR1. A transistor TR, a source lineSL, a word line WL and other semiconductor components may be provided inthe second memory region AR2. A plurality of conductive patterns CP maybe provided in the interlayer insulating layer 101 on the second memoryregion AR2.

Referring to FIG. 3B, a sub-bottom electrode material layer SBL, aselection element material layer SWL, a first bottom electrode materiallayer BEL1, and a first hard mask layer HM1 may be sequentiallydeposited on the first memory region AR1 and the second memory regionAR2. The first hard mask layer HM1 may include, e.g., silicon oxide,silicon nitride, a metal oxide, or a metal nitride. The selectionelement material layer SWL may be deposited by, e.g., an atomic layerdeposition (ALD) process, a physical vapor deposition (PVD) process, ora co-sputtering process.

Referring to FIG. 3C, the selection element material layer SWL, thefirst bottom electrode material layer BEL1 and the first hard mask layerHM1 on the second memory region AR2 may be removed.

For example, a mask pattern covering the first memory region AR1 may beformed. For example, the mask pattern may be formed by coating,exposure, and development processes of a photoresist. Next, the firsthard mask layer HM1, the first bottom electrode material layer BEL1, andthe selection element material layer SWL on the second memory regionAR2, which are not covered by the mask pattern, may be etched. At thistime, a top surface of the sub-bottom electrode material layer SBL maybe used as an etch stop line. As a result, the selection elementmaterial layer SWL and the first bottom electrode material layer BEL1may remain locally on the first memory region AR1.

Referring to FIG. 3D, a second bottom electrode material layer BEL2 maybe deposited on the first memory region AR1 and the second memory regionAR2. Subsequently, a first insulating layer DL1 may be formed on thefirst memory region AR1 and the second memory region AR2.

The first insulating layer DL1 may be thickly deposited in such a waythat a height difference hardly occurs between a top surface of thefirst insulating layer DL1 on the first memory region AR1 and a topsurface of the first insulating layer DL1 on the second memory regionAR2.

Referring to FIG. 3E, a planarization process may be performed on thefirst memory region AR1 and the second memory region AR2. For example,the planarization process may include a chemical mechanical polishing(CMP) process. A bottom surface of the first hard mask layer HM1 on thefirst memory region AR1 may be used as a stop line of the planarizationprocess.

The first bottom electrode material layer BEL1 on the first memoryregion AR1 and the second bottom electrode material layer BEL2 on thesecond memory region AR2 may be exposed to the outside by theplanarization process. In addition, due to the planarization process. alevel of a top surface of the first bottom electrode material layer BEL1on the first memory region AR1 may be substantially the same as a levelof a top surface of the second bottom electrode material layer BEL2 onthe second memory region AR2 (e.g., the top surface of the first bottomelectrode material layer BEL1 on the first memory region AR1 may besubstantially coplanar with the top surface of the second bottomelectrode material layer BEL2 on the second memory region AR2).

Referring to FIG. 3F, a first variable resistance material layer RL1, afirst top electrode material layer TEL1 and a second hard mask layer HM2may be sequentially deposited on the first memory region AR1 and thesecond memory region AR2. The second hard mask layer HM2 may be formedof, e.g., silicon oxide, silicon nitride, a metal oxide, or a metalnitride by a deposition process.

Referring to FIG. 3G, the first variable resistance material layer RL1,the first top electrode material layer TEL1, and the second hard masklayer HM2 on the second memory region AR2 may be etched. For example, amask pattern covering the first memory region AR1 may be formed. Forexample, the mask pattern may be formed by coating, exposure, anddevelopment processes of a photoresist. Next, the second hard mask layerHM2, the first top electrode material layer TEL1, and the first variableresistance material layer RL1 on the second memory region AR2, which arenot covered by the mask pattern, may be etched. As a result, the firstvariable resistance material layer RL1 and the first top electrodematerial layer TEL1 may remain locally on the first memory region AR1.

Referring to FIG. 3H, a second variable resistance material layer RL2, asecond top electrode material layer TEL2, and a second insulating layerDL2 may be sequentially formed on the first memory region AR1 and thesecond memory region AR2. The second insulating layer DL2 may be thicklyformed in such a way that a level (or height) difference hardly occursbetween a top surface of the second insulating layer DL2 on the firstmemory region AR1 and a top surface of the second insulating layer DL2on the second memory region AR2.

Referring to FIG. 3I, a planarization process may be performed on thefirst memory region AR1 and the second memory region AR2. For example,the planarization process may include a chemical mechanical polishing(CMP) process. A bottom surface of the second hard mask layer HM2 on thefirst memory region AR1 may be used as a stop line of the planarizationprocess. The first top electrode material layer TEL1 on the first memoryregion AR1 and the second top electrode material layer TEL2 on thesecond memory region AR2 may be exposed by the planarization process.The planarization process may be performed until a level of a topsurface of the first top electrode material layer TEL1 on the firstmemory region AR1 is substantially the same as a level of a top surfaceof the second top electrode material layer TEL2 on the second memoryregion AR2.

Referring again to FIG. 2, a cell patterning process may be performed onthe first memory region AR1 and the second memory region AR2 at the sametime. For example, the cell patterning process may be performed using aphotolithography process for forming mask patterns and an etchingprocess. The sub-bottom electrode material layer SBL, the selectionelement material layer SWL, the first bottom electrode material layerBEL1, the first variable resistance material layer RL1, and the firsttop electrode material layer TEL1 on the first memory region AR1 may beformed into a plurality of first memory cells MC1 through the cellpatterning process.

The sub-bottom electrode material layer SBL, the second bottom electrodematerial layer BEL2, the second variable resistance material layer RL2,and the second top electrode material layer TEL2 on the second memoryregion AR2 may be formed into a plurality of second memory cells MC2through the cell patterning process.

In addition, a second conductive line CL2 electrically connected to thefirst memory cells MC1 may be formed, and a third conductive line CL3electrically connected to the second memory cells MC2 may be formed.

FIG. 4 illustrates a cross-sectional view of a variable resistancememory device according to some embodiments. Hereinafter, repeateddescriptions to the same components and features as mentioned withreference to FIG. 2 may be omitted for the purpose of ease andconvenience in explanation.

Referring to FIG. 4, a variable resistance memory device 3000 accordingto the present embodiments may include a substrate 100, a first memorydevice MD1, and a second memory device MD2.

The substrate 100 may include a first memory region AR1 and a secondmemory region AR2. Transistors TR, source lines SL and word lines WL maybe provided in the first memory region AR1 and the second memory regionAR2.

A plurality of conductive patterns CP may be provided in an interlayerinsulating layer 101 on the substrate 100. In an implementation, topsurfaces of the conductive patterns CP may be coplanar with a topsurface of the interlayer insulating layer 101.

The first memory device MD1 may include a plurality of first memorycells MC1. Each of the first memory cells MC1 may include a firstresistance element RD1. The first resistance element RD1 may include afirst bottom electrode BE1, a first variable resistance pattern RP1, anda first top electrode TE1, which are sequentially stacked in the thirddirection D3.

A conductive line CL may be provided on the first memory device MD1.

The second memory device MD2 may include a plurality of second memorycells MC2. Each of the second memory cells MC2 may include a secondresistance element RD2. The second resistance element RD2 may include asecond bottom electrode BE2, a second variable resistance pattern RP2,and a second top electrode TE2, which are sequentially stacked in thethird direction D3.

A conductive line CL may be provided on the second memory device MD2.

In relation of the first memory device MD1 and the second memory deviceMD2, the second variable resistance pattern RP2 may include a differentmaterial from that of the first variable resistance pattern RP1. Forexample, when the same voltage is applied to the first and secondvariable resistance patterns RP1 and RP2, the amount of a currentflowing through the second variable resistance pattern RP2 may begreater than the amount of a current flowing through the first variableresistance pattern RP1. For example, the first variable resistancepattern RP1 may have a resistance state that is greater than that of thesecond variable resistance pattern RP2. In an implementation, themaximum value of a variable resistance of the second resistance elementRD2 may be less than the maximum value of a variable resistance of thefirst resistance element RD1.

A level of a top surface T1 of the first top electrode TE1 may be thesame or substantially the same as a level of a top surface T2 of thesecond top electrode TE2.

FIGS. 5A to 5F illustrate cross-sectional views of stages in a method ofmanufacturing a variable resistance memory device according to someembodiments. Hereinafter, repeated descriptions to the same componentsand features as mentioned with reference to FIGS. 3A to 3I may beomitted for the purpose of ease and convenience in explanation.

Referring to FIG. 5A, a substrate 100 (including a first memory regionAR1 and a second memory region AR2) may be provided. Transistors TR,source lines SL and word lines WL may be provided in the first memoryregion AR1 and the second memory region AR2. A plurality of conductivepatterns CP may be provided in an interlayer insulating layer 101 on thesubstrate 100.

Referring to FIG. 5B, a first bottom electrode material layer BEL1, asecond variable resistance material layer RL2, a second top electrodematerial layer TEL2, and a hard mask layer HM may be sequentiallydeposited on the first memory region AR1 and the second memory regionAR2.

Referring to FIG. 5C, the hard mask layer HM, the second top electrodematerial layer TEL2, and the second variable resistance material layerRL2 on the first memory region AR1 may be removed.

Referring to FIG. 5D, a first variable resistance material layer RL1, afirst top electrode material layer TEL1, and an insulating layer DL maybe sequentially formed on the first memory region AR1 and the secondmemory region AR2. The insulating layer DL may be thickly deposited insuch a way that a height difference hardly occurs between a top surfaceof the insulating layer DL on the first memory region AR1 and a topsurface of the insulating layer DL on the second memory region AR2.

Referring to FIG. 5E, a planarization process may be performed on theinsulating layer DL on the first memory region AR1 and the second memoryregion AR2. When the first top electrode material layer TEL1 on thesecond memory region AR2 is exposed, a portion of the insulating layerDL may remain on the first memory region AR1.

Referring to FIG. 5F, the planarization process may further be performedon the first memory region AR1 and the second memory region AR2. Abottom surface of the hard mask layer HM may be used as a stop line ofthe planarization process.

The first top electrode material layer TEL1 on the first memory regionAR1 and the second top electrode material layer TEL2 on the secondmemory region AR2 may be exposed to the outside by the planarizationprocess. In addition, a level of a top surface of the first topelectrode material layer TEL1 on the first memory region AR1 may besubstantially the same as a level of a top surface of the second topelectrode material layer TEL2 on the second memory region AR2.

Referring again to FIG. 4, a cell patterning process may be performed onthe first memory region AR1 and the second memory region AR2 at the sametime. In addition, a conductive line CL electrically connected to thefirst memory cells MC1 may be formed, and a conductive line CLelectrically connected to the second memory cells MC2 may be formed. Forexample, during the cell patterning process, the first bottom electrodematerial layer BEL1, the first variable resistance material layer RL1,and the first top electrode material layer TEL1 may be patterned to formthe first bottom electrode BE1, the first variable resistance patternRP1, and the first top electrode TE1 of the first memory cells MC1, andthe first bottom electrode material layer BEL1, the second variableresistance material layer RL2, and the second top electrode materiallayer TEL2 may be patterned to form the second bottom electrode BE2, thesecond variable resistance pattern RP2, and the second top electrode TE2of the second memory cells MC2,

FIG. 6 illustrates a cross-sectional view of a variable resistancememory device according to some embodiments. Hereinafter, repeateddescriptions to the same components and features as mentioned withreference to FIG. 2 may be omitted for the purpose of ease andconvenience in explanation.

Referring to FIG. 6, a variable resistance memory device 4000 accordingto the present embodiments may include a substrate 100, a first memorydevice MD1, and a second memory device MD2. The substrate 100 mayinclude a first memory region AR1 and a second memory region AR2. Aninterlayer insulating layer 101 may be provided on the substrate 100. Aplurality of first conductive lines CL1 may be provided in theinterlayer insulating layer 101. The plurality of first conductive linesCL1 may be, e.g., word lines or bit lines. Each of the first conductivelines CL1 may extend in the first direction D1 parallel to a top surfaceof the substrate 100.

The first memory device MD1 may be on the first memory region AR1. Thefirst memory device MD1 may include a plurality of first memory cellsMC1. Each of the first memory cells MC1 may include a first resistanceelement RD1 and a selection element SW. In an implementation, each ofthe first memory cells MC1 may further include a sub-bottom electrodeBS. The sub-bottom electrode BS, the selection element SW, and the firstresistance element RD1 may be sequentially stacked in the thirddirection D3. The first resistance element RD1 may include a firstbottom electrode BE1, a first variable resistance pattern RP1, and afirst top electrode TE1, which are sequentially stacked in the thirddirection D3.

The second memory device MD2 may include a plurality of second memorycells MC2. The second memory cells MC2 may be spaced apart from eachother in the second direction D2. Each of the second memory cells MC2may include a second resistance element RD2 and a selection element SW.In an implementation, each of the second memory cells MC2 may furtherinclude a sub-bottom electrode BS. The sub-bottom electrode BS, theselection element SW, and the second resistance element RD2 may besequentially stacked in the third direction D3. The second resistanceelement RD2 may include a second bottom electrode BE2, a second variableresistance pattern RP2, and a second top electrode TE2, which aresequentially stacked in the third direction D3.

Second conductive lines CL2 may be on the first memory device MD1 andthe second memory device MD2. The first conductive lines CL1, the firstmemory cells MC1, and the second conductive lines CL2 on the firstmemory region AR1 may constitute a cross point structure. The firstconductive lines CL1, the second memory cells MC2, and the secondconductive lines CL2 on the second memory region AR2 may constitute across point structure.

In relation of the first memory device MD1 and the second memory deviceMD2, the second variable resistance pattern RP2 may include a differentmaterial from that of the first variable resistance pattern RP1. Whenthe same voltage is applied to the first and second variable resistancepatterns RP1 and RP2, the amount of a current flowing through the secondvariable resistance pattern RP2 may be greater than the amount of acurrent flowing through the first variable resistance pattern RP1. Forexample, the first variable resistance pattern RP1 may have a resistancestate that is greater than that of the second variable resistancepattern RP2. In an implementation, the maximum value of a variableresistance of the second resistance element RD2 may be less than themaximum value of a variable resistance of the first resistance elementRD1.

A level of a top surface T1 of the first top electrode TE1 may be thesame or substantially the same as a level of a top surface T2 of thesecond top electrode TE2.

FIGS. 7A to 7F illustrate cross-sectional views of stages in a method ofmanufacturing a variable resistance memory device according to someembodiments. Hereinafter, repeated descriptions to the same componentsand features as mentioned with reference to FIGS. 3A to 3I may beomitted for the purpose of ease and convenience in explanation.

Referring to FIG. 7A, a substrate 100 including a first memory regionAR1 and a second memory region AR2 may be provided. An interlayerinsulating layer 101 may be provided on the substrate 100. A pluralityof first conductive lines CL1 may be provided in the interlayerinsulating layer 101. The plurality of first conductive lines CL1 maybe, e.g., word lines or bit lines. Each of the first conductive linesCL1 may extend in the first direction D1 parallel to a top surface ofthe substrate 100.

Referring to FIG. 7B, a sub-bottom electrode material layer SBL, aselection element material layer SWL, a first bottom electrode materiallayer BEL1, a second variable resistance material layer RL2, a secondtop electrode material layer TEL2, and a hard mask layer HM may besequentially deposited on the first memory region AR1 and the secondmemory region AR2.

Referring to FIG. 7C, the hard mask layer HM, the second top electrodematerial layer TEL2, and the second variable resistance material layerRL2 on the first memory region AR1 may be removed.

Referring to FIG. 7D, a first variable resistance material layer RL1 anda first top electrode material layer TEL1 may be sequentially depositedon the first memory region AR1 and the second memory region AR2.Subsequently, an insulating layer DL may be formed on the first memoryregion AR1 and the second memory region AR2. The insulating layer DL maybe thickly deposited in such a way that a height difference hardlyoccurs between a top surface of the insulating layer DL on the firstmemory region AR1 and a top surface of the insulating layer DL on thesecond memory region AR2.

Referring to FIG. 7E, a planarization process may be performed on theinsulating layer DL on the first memory region AR1 and the second memoryregion AR2. When the first top electrode material layer TEL1 on thesecond memory region AR2 is exposed, a portion of the insulating layerDL may remain on the first memory region AR1.

Referring to FIG. 7F, the planarization process may further be performedon the first memory region AR1 and the second memory region AR2. Forexample, the planarization process may include a chemical mechanicalpolishing (CMP) process. A bottom surface of the hard mask layer HM onthe second memory region AR2 may be used as a stop line of theplanarization process.

The first top electrode material layer TEL1 on the first memory regionAR1 and the second top electrode material layer TEL2 on the secondmemory region AR2 may be exposed to the outside by the planarizationprocess. In addition, a level of a top surface of the first topelectrode material layer TEL1 on the first memory region AR1 may besubstantially the same as a level of a top surface of the second topelectrode material layer TEL2 on the second memory region AR2.

Referring again to FIG. 6, a cell patterning process may be performed onthe first memory region AR1 and the second memory region AR2 at the sametime. For example, a second conductive line CL2 electrically connectedto the first memory cells MC1 may be formed, and a second conductiveline CL2 electrically connected to the second memory cells MC2 may beformed. For example, during the cell patterning process, the sub-bottomelectrode material layer SBL, the selection element material layer SWL,the first bottom electrode material layer BEL1, the first variableresistance material layer RL1, and the first top electrode materiallayer TEL1 may be patterned to form the sub-bottom electrode BS, theselection element SW, the first bottom electrode BE1, the first variableresistance pattern RP1, and the first top electrode TE1 of the firstmemory cells MC1, and the sub-bottom electrode material layer SBL, theselection element material layer SWL, the first bottom electrodematerial layer BEL1, the second variable resistance material layer RL2,and the second top electrode material layer TEL2 may be patterned toform the sub-bottom electrode BS, the selection element SW, the secondbottom electrode BE2, the second variable resistance pattern RP2, andthe second top electrode TE2 of the second memory cells MC2.

By way of summation and review, next-generation semiconductor memorydevices (e.g., ferroelectric random access memory (FRAM) devices,magnetic random access memory (MRAM) devices, and phase-change randomaccess memory (PRAM) devices) may provide high-performance and low powerconsuming semiconductor memory devices. Materials of thesenext-generation semiconductor memory devices may have resistance valuesvariable according to currents or voltages applied thereto and mayretain their resistance values even when currents or voltages areinterrupted.

According to the embodiments, the first memory cell having high storageability and the second memory cell having a high processing speed may beformed on a single chip, and efficiency of the chip may be improved ormaximized. In addition, a height difference between the first and secondmemory cells may hardly exist, and a margin in a subsequentphotolithography process may be secured.

Performance of an entire chip may be improved using the variableresistance memory device according to the embodiments.

One or more embodiments may provide a variable resistance memory devicecapable of improving or maximizing efficiency of a semiconductor chip.

Example embodiments have been disclosed herein, and although specificterms are employed, they are used and are to be interpreted in a genericand descriptive sense only and not for purpose of limitation. In someinstances, as would be apparent to one of ordinary skill in the art asof the filing of the present application, features, characteristics,and/or elements described in connection with a particular embodiment maybe used singly or in combination with features, characteristics, and/orelements described in connection with other embodiments unless otherwisespecifically indicated. Accordingly, it will be understood by those ofskill in the art that various changes in form and details may be madewithout departing from the spirit and scope of the present invention asset forth in the following claims.

What is claimed is:
 1. A variable resistance memory device, comprising:a substrate including a first memory region and a second memory region;a plurality of first memory cells on the first memory region; and aplurality of second memory cells on the second memory region, wherein:each of the first memory cells includes a first resistance element and aselection element, each of the second memory cells includes a secondresistance element, and a maximum value of a variable resistance of thesecond resistance element is less than a maximum value of a variableresistance of the first resistance element.
 2. The variable resistancememory device as claimed in claim 1, further comprising: a firstconductive line electrically connected to each of the first memory cellsand between each of the first memory cells and the substrate; a secondconductive line electrically connected to the first memory cells and onthe first memory cells; and a transistor electrically connected to eachof the second memory cells, the transistor being in the substrate,wherein: the first conductive line extends in a first direction parallelto a top surface of the substrate, and the second conductive lineextends in a second direction parallel to the top surface of thesubstrate and perpendicular to the first direction.
 3. The variableresistance memory device as claimed in claim 1, wherein: the firstresistance element includes a first bottom electrode, a first topelectrode on the first bottom electrode, and a first variable resistancepattern between the first bottom electrode and the first top electrode,the second resistance element includes a second bottom electrode, asecond top electrode on the second bottom electrode, and a secondvariable resistance pattern disposed between the second bottom electrodeand the second top electrode, and a level of a top surface of the firsttop electrode is substantially the same as a level of a top surface ofthe second top electrode.
 4. The variable resistance memory device asclaimed in claim 3, wherein a level of a top surface of the first bottomelectrode is substantially the same as a level of a top surface of thesecond bottom electrode.
 5. The variable resistance memory device asclaimed in claim 3, wherein: each of the first variable resistancepattern and the second variable resistance pattern independently includea metal oxide; and the first variable resistance pattern and the secondvariable resistance pattern include different materials from each other.6. The variable resistance memory device as claimed in claim 3, whereina level of a bottom surface of the first bottom electrode is higher thana level of a bottom surface of the second bottom electrode.
 7. Thevariable resistance memory device as claimed in claim 1, wherein athickness of the first resistance element in a third directionperpendicular to a top surface of the substrate is less than a thicknessof the second resistance element in the third direction.
 8. The variableresistance memory device as claimed in claim 1, further comprising: afirst sub-bottom electrode between the first resistance element and thesubstrate; and a second sub-bottom electrode between the secondresistance element and the substrate, wherein the first sub-bottomelectrode, the selection element, and the first resistance element aresequentially stacked in the first memory cell.
 9. The variableresistance memory device as claimed in claim 8, wherein a level of a topsurface of the first sub-bottom electrode is substantially the same as alevel of a top surface of the second sub-bottom electrode.
 10. Thevariable resistance memory device as claimed in claim 1, wherein theselection element includes a PN diode, an ovonic threshold switch (OTS)element, or a mixed ionic electronic conductor (MIEC).
 11. A method ofmanufacturing a variable resistance memory device, the methodcomprising: forming a bottom electrode material layer on a substratethat includes a first memory region and a second memory region; forminga first variable resistance material layer on the bottom electrodematerial layer; forming a first top electrode material layer on thefirst variable resistance material layer; removing the first variableresistance material layer and the first top electrode material layer onthe second memory region; forming a second variable resistance materiallayer on the substrate; forming a second top electrode material layer onthe second variable resistance material layer; removing the secondvariable resistance material layer and the second top electrode materiallayer on the first memory region; and patterning the bottom electrodematerial layer, the first variable resistance material layer, the secondvariable resistance material layer and the first and second topelectrode material layers, which remain on the substrate, to form firstmemory cells on the first memory region and second memory cells on thesecond memory region, wherein: removing the second variable resistancematerial layer and the second top electrode material layer on the firstmemory region includes performing a planarization process to expose thefirst top electrode material layer on the first memory region, and thefirst variable resistance material layer includes a material of which amaximum resistance value is different from that of a material of thesecond variable resistance material layer.
 12. The method as claimed inclaim 11, wherein the planarization process is performed until a levelof a top surface of the first top electrode material layer on the firstmemory region is substantially the same as a level of a top surface ofthe second top electrode material layer on the second memory region. 13.The method as claimed in claim 11, wherein each of the first memorycells and the second memory cells is electrically connected to atransistor in the substrate.
 14. The method as claimed in claim 11,further comprising forming a selection element material layer on thesubstrate such that the selection element material layer is between thebottom electrode material layer and the substrate.
 15. The method asclaimed in claim 11, wherein forming the first variable resistancematerial layer and forming the second variable resistance material layerindependently include performing an atomic layer deposition (ALD)process, a physical vapor deposition (PVD) process, or a co-sputteringprocess.
 16. The method as claimed in claim 11, further comprisingforming a selection element material layer on one of the first memoryregion and the second memory region such that wherein the selectionelement material layer is between the bottom electrode material layerand the substrate.
 17. The method as claimed in claim 11, wherein eachof the first variable resistance material layer and the second variableresistance material layer includes an oxide including Ti, Zr, Al, Hf, orSi.
 18. The method as claimed in claim 11, further comprising: forming afirst conductive line electrically connected to each of the first memorycells, the first conductive line being on the first memory region andbetween each of the first memory cells and the substrate; and forming asecond conductive line electrically connected to the first memory cells,the second conductive line being on the first memory cells, wherein: thesecond memory region includes a transistor electrically connected toeach of the second memory cells, the first conductive line extends in afirst direction parallel to a top surface of the substrate, and thesecond conductive line extends in a second direction parallel to the topsurface of the substrate and perpendicular to the first direction. 19.The method as claimed in claim 11, wherein the planarization processincludes a chemical mechanical polishing (CMP) process.
 20. The methodas claimed in claim 11, further comprising forming a sub-bottomelectrode material layer on the substrate.